Systematic Explosions
by natanije
Summary: Gokudera Hayato died amidst explosions. He died protecting his boss, his best friend. He didn't regret it much and was ready for oblivion, even Heaven or Hell. Which is why, he's surprised that he finds himself in a world full of UMAs instead. (Or, Gokudera Hayato awakens as Bakugou Katsuki, and the changes that follow).
1. Chapter 1

**Systematic Explosions**

 **Summary:** Gokudera Hayato died amidst explosions. He died protecting his boss, his best friend. He didn't regret it much and was ready for oblivion, even Heaven or Hell. Which is why, he's surprised that he finds himself in a world full of UMAs instead.

(Or, Gokudera Hayato awakens as Bakugou Katsuki, and the changes that follow).

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.

 **[PROLOGUE: Awakening]**

For someone smack dab in the mafia, death is but an inescapable reality. It may happen any moment possible. It'll even come faster if you're not alert of your surroundings. Even regular people would not deny that they will die eventually (except for some people who are, like, say, Byakuran, and maybe Vindice). Hayato knew this, really. He knew, _knows_ —that with his position in the mafia, as Vongola Tenth's right hand man and Storm Guardian, he would have to perish sooner or later. That is why… He thought that he had to be strong, to be powerful. Because knowing that death is inescapable didn't mean that he would stop trying to _live_ or keeping his family alive. Hayato was nothing but a stubborn mule and he'd be damned if he let his friends or himself be killed _that_ easily.

But even the strongest of men perish eventually, weren't they?

( _The old Byakuran was killed by then-middle-schooler Tenth. He was burned when he prided himself as strongest and even beyond human._

 _Bermuda was defeated when he was supposed to be the Strongest Arcobaleno._

 _At the end of the day, the term 'strongest' is nothing but a fleeting title, is it not?_ )

Everyone would perish eventually.

And Hayato…

Hayato is no exception.

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.

Gokudera Hayato died at the age of 29 by doing what he does best: protecting his boss, his best friend. It was a bit ironic, to die in an explosion when his weapons include using explosions, but— _well_. Fate had always liked irony, hadn't it?

Tenth—Tsuna would probably yell at him when they meet sometime in the far, far future. (God, does he hope that they'll meet again in a _long_ while. While his life had to end so abruptly, he wanted— _hoped_ —that his boss and the rest of his family would get to _live_. That they would grow old, have a peaceful retirement, and die peacefully). Hayato would like meeting his family in the afterlife, and he totally did not regret— _does not regret_ —protecting him.

Even at the cost of his life.

( _He had promised, once, that he'd live. He'd_ live, _because he wanted to see the fireworks once again._

 _He kept to his promise, back then._

 _He just couldn't. Not this time._

He thought he could've survived. Thought he could _live_.

I'm sorry, Tenth.

I'm sorry.

Ḯ̸̧̢̥͈̞͉̞͕̰̄͆͛̽̍͂̓̚͠'̵̧̛̛̬͈̭͎͈̭̗̌̈́̿͋̌͊͝͝m̶̟̀̂͒̽ ̵̢̥͖̼̮̮̬͂̉̌͂̍̉̑͗̀̓ͅs̴̡̨͖̪̳͇͔̯̑͝o̶̝̘͈̤͛́̍͒́̋̃̕͠r̵̝̭̱̥̯̽͆̒̒ŗ̶͙͉̹̯̗͉̋̓̾̇̌̅́͂̚͜ÿ̴͍̣͔͔̦̩̳̬̦́ͅ)

His only regret was that he wouldn't be able to say goodbye, that by dying, he couldn't spend his time with his family anymore.

( _He regretted that he wasn't strong enough to survive_ ).

.

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Gokudera Hayato died in the midst of explosions, having thrown his best friend out of the building before his world bled red and turned dark.

Gokudera Hayato wakes up when something exploded on his face, his body stumbling backward in shock as he blinks away black spots on his vision. He lands on his butt, sitting dumbly in what can only be a bathroom, blinking as he tries to remember how he gets here.

He doesn't understand, he thinks, mouth pulled downwards in a frown. He tries to think—of something, _anything_. He… what was he doing? What happened? He's… he's pretty sure that… that he should've…

He should be _dead_.

He—That mission was _real_. He was not dreaming, he's sure of it. It was so _vivid,_ so _real_. He can still taste the desperation in his tongue, his panic and need to get his best friend out of the way, _Tsuna, get away, Boss, please run pleASE RUN TAKE MY HAND_ _ **P GET OUT RIGHT NO W**_ _—_

Red.

Redredredred **redredreredredredredredred—** _ **PAIN THERES SO M UC H P AIN IT HU RSTT S IT HU RTS SSTSS IT HURTSTSS**_

 _ **I̵̛̙͉̽̎̄̌́͘͝͠͠'̴̨̛͖̑̊̂̎͐̀́̔͂m̷̨̩̮̲͐̔͆͌̈́̕**_

Ì̴̦̰̗͙̜̖̜͐̅̾͠ṯ̶͈̹̇̈̀̀ ̷̛̺͖̣̹̲̩̙̉̈̄̇͂͐̈́̚͝h̸̼͉̗̀̔̋̆ų̷̢͕͔͈͓̦̭̱̟̀̈́̀̃r̴̭̤̍͂̿̅̊͋t̸̡̑̓̃̏̆̒s̶̰̖͎̉̽͗͌̓̋͊

" _Katsuki?!_ " A shrill voice cut off his rapid thoughts, and Hayato jolts back to reality, belatedly realizing how he's gotten hold of his hair into his fists, pulling and pulling as he struggles to breathe.

A woman—blonde, short spiky hair that can put Sasagawa's into shame—kneels in front of him, shoulders tight and eyebrows furrowed in nothing but panic and genuine _worry_ , and Hayato jolts, surprised, because—

Because—

She's so _big_. So _tall_ and much, much bigger than him and he finds that he's kneeling, now, but he's so _short_ that his head doesn't even reach the sink and—and he was… when he stumbled, he was… standing on top of a small chair?

"Katsuki, hey, what's wrong with you?!" The woman's voice is audible, but Hayato is not keen to listen as his gaze moves rapidly, taking in the unfamiliar surroundings, how everything looks so _big_ and it's wrong, it's so _wrong_ —

"Katsuki!" Hands grasp his shoulders, tense and yet so, so _gentle_ somehow, and—and Hayato looks up, looks at the woman who should've been shorter than Hayato and yet, and _yet_ —

"Katsuki," the woman is calling him, he finally realizes. She's speaking to _him_ , but—but the name is _wrong_.

Katsuki?

His name isn't—

"Katsuki, what's wrong? I heard an explosion," explosion, red, red, _red,_ pain so m **uCH PA** _ **IN**_ **—** Explosion on his face, stumbling on top of an innocent mini chair usually used by children, a woman calling him _Katsuki_ —

"Did you activate your quirk? Katsuki, baby, I won't understand if you don't speak to me. What's wrong, you're usually very noisy, baby, please talk to me, I won't know what's wrong if you don't speak—" The woman chokes on her words, rubbing comforting circles behind Hayato's neck and, and the hands—so warm and so _familiar_ , even though it shouldn't be, because he doesn't know this woman, doesn't know this blonde who calls him Katsuki and looks so worried she could probably burst into tears and yet so _strong_ as she yells at him to snap out of it, her hoarse voice yelling for her _darling_ to come and help because—

"—He won't reply to me, he's just staring into _nothing!_ I don't know what to do, I don't—Is it a quirk activation gone wrong? I don't—Katsuki, please answer me, answer Mommy. I'll buy the All Might figurine you bitch about if you answer me right now, God, Katsuki!"

Hayato looks down.

He looks at his small legs, his small hands and pudgy fingers.

He _looks_.

(He _remembers_ ).

.

.

.

He died.

.

.

.

His world goes black, once more.

.

.

.

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Bakugou Katsuki activates his quirk for the first time when he's four, one that is subsequently followed by a small panic attack that causes his parents to worry before he falls unconscious, sending his parents into a _more_ panicked frenzy.

His last words before he falls unconscious are nothing but a pathetic, confused whine of:

"Plus Ultra...?"

.

.

(In Katsuki's defense, years later when his mother would tease him about it, he really _wanted_ that All Might figurine.

It's just his luck he managed to get it because he was in a little bit of an… identity crisis, you could say.

Really, really. It's not like he was thinking about how he was blown into smithereens. Nope. Not at all.

Really.)


	2. Chapter 2

**Systematic Explosions**

 **Summary:** Gokudera Hayato died amidst explosions. He died protecting his boss, his best friend. He didn't regret it much and was ready for oblivion, even Heaven or Hell. Which is why, he's surprised that he finds himself in a world full of UMAs instead.

(Or, Gokudera Hayato awakens as Bakugou Katsuki, and the changes that follow).

.

.

 **[ONE: A World of UMAs]**

Adjusting into a new world is… strange.

Perhaps Hayato has been lucky, because Bakugou Katsuki is not yet a fully grown man, but an impressionable child with no complicated background. It's way easier for Hayato to become Katsuki and Katsuki to be one with Hayato than what it would've been if Katsuki is a bit older.

And now Hayato is—no more.

He's Katsuki now, isn't he?

Bakugou Katsuki, a four year old with spiky unruly blond hair that seems like a mix between turf top, baseball idiot and the Tenth, a _child_ who just awakened his quirk. And alongside said quirk, comes Hayato with his memories and feelings and trauma and experiences all jumbled together—crammed inside a child's brain.

Fuck, is this how Byakuran feels in every parallel world, where he gets the numerous information from other worlds? No wonder Byakuran is a bit strange, all those worlds and their own uniqueness jumbling together—you get to start wondering which one is real.

Katsuki lets himself wonder if what he experiences right now is even real.

He tries to think that perhaps Gokudera Hayato is just a figment of imagination, a fantasy made by a four year old's too excited brain, but he doesn't exactly manage to do that for long. It hurt: to think that Hayato and his life were mere imagination. Katsuki can still remember it as clear as day: the days of Hayato's childhood, the pain and the suffering, thinking that he was not good enough, that there were no places that would accept the bastard child Hayato had been. He had been so eager to get recognition, to get a _family_ , to the point where he became so devoted, so _so_ reckless. He remembers Sawada Tsunayoshi, he remembers his Famiglia, the fun times spent with them as well as the countless battles. He remember how he as Hayato loved them (still does, even if he's Katsuki now), how Hayato so _fiercely_ loved them. He remembers the many hours spent pouring over battle strategies, the feel of guns and explosives on his hands, the red flame that signified his resolve to _protect, to live_ —

He remembers his death. And in addition to it, his very own awakening.

Hayato may think that this is a fantasy made, a weird sort of purgatory for a killer like him but, but—it's also very unlikely.

The only thing he can think of is, that this is—

( _"I have gone past the cycles of rebirth_ ," _Mukuro sneered, his lone red eye glowing eerily._ )

Katsuki sighs, his red eyes glancing out from the window.

Mukuro is a fucking liar, Katsuki thinks. That damn pineapple didn't say that getting reborn in the middle of UMAs is a possibility, as well. Then again, he's read of conspiracy theories about alternate universes. If parallel worlds and six realms of rebirth exist, why not alternate universes with UMAs roaming about freely?

.

.

Anyway.

This world is fucking strange, that's what Katsuki (Hayato? He's Hayato, but he's also Katsuki. It's all very confusing, but at the end of the day, people here refer to him as Katsuki, and thus he shall be Katsuki. He will always treasure Hayato as his name, his identity, but here—he'll let himself to be Katsuki) thinks. First of all, it's fucking weird that his hands seem to make explosions on their own.

Well, not their own. Apparently it's because of his sweat. He can make his sweat _explode_ , how fucking weird is that? He's seen enough Marvel movies as Hayato enough that he was worried, at first, when the doctor told him about this simple fact in front of his parents (and isn't that weird, to find himself with _parents._ The biological ones, too. The ones who seem to _really_ care about him without any sudden death drama or illegitimate child drama, too). What if his parents reject him? Think him a freak? Send him to weird lab doctors to dissect? He'll end up as a second Mukuro or Ken (thanks to the blond hair) and Katsuki doesn't really _want_ that.

But it never happened.

His mother had simply stated, "I see," and fussed over Katsuki once again, asking if he's accidentally blown up his hands in front of his own face or something (he did) and if he went to shock because of it (he did went to shock, but not because of the explosions, exactly. Though maybe explosion was the trigger? Death by explosion, awakening by explosion. Katsuki can taste the irony with his tongue and it's _salty_ ).

He had been… confused, over how accepting they were of his apparent 'super power'.

But then he found out he's not the only one.

So here Katsuki is, marveling about the existence of _quirks_. The reveal of said word makes Katsuki four-year-old memories to settle itself, and Katsuki _understands_. This world… it has quirks. People have _abilities._ It varies from people to people, but the point is that right now, the world is nothing but a superhuman society.

And isn't that _fucking weird_.

He's seen weird people when he was Hayato. Heck, he was pretty weird himself. He could stuff numerous bombs under his clothes, more than normal people would be able to (there's a trick to it, and whether he's Hayato or Katsuki, he ain't sharing it to anybody else). The idiot cow, when he was still tiny, he could stuff a whole _bazooka_ and other knick knacks in his afro. Reborn-san was able to use ridiculous costumes without anyone figuring out it was _him_ (and that had been a pretty shocking wake up call, when Tsuna revealed that apparently, Reborn-san once dressed as a _flower pot_ when he was still an Arcobaleno. Hayato actually _wheezed_ ). Turf top ran around the whole Japan searching for Kyoko when they were trapped in the future (seriously, _how the fuck_?). Hibari had an army of small yellow birds following him (the only thing scary about Hibari, in Hayato's _humble_ opinion). Hayato didn't know how Kusakabe managed his hair. Yuni was an _alien_. Byakuran could sprout _wings_. Daemon's ghost lingered for _years_ because he was so hung up about his dead girlfriend. Mukuro used Chrome's body as his vessel for years and joked about getting other people's bodies for many more years to come. There was a kid in Varia who used _frog hat as decoration and **he was a fucking elite assassin**_.

Yeah, Hayato—now Katsuki—is pretty used with a whole brand of weird.

For the whole world to join in the weird bandwagon, though? Fucking weird.

It's not hard for Katsuki to assume that he's in a whole new world altogether (the year number isn't too far off from the time Hayato had died, but 'quirks' had been around for far too long in this world), and although he's sad—does this mean there's _no Vongola?_ No Tenth, no Famiglia for him to return to, no one—he's also pretty stupefied about it.

He wonders, for awhile, if someone higher up finds it funny to make Hayato reborn in a world full of UMAs. Because he had been a fan of UMAs (still kinda is. Mitsuki wonders since when her son likes alien shows _that_ much).

At least it gives him something to distract himself with. Gives him things to focus on other than the pain and grief and the _nightmares_ surrounding his past life and his death ( _I'm sorry Tenth I'm not strong enough I'm sorry I'm sorry **I'm sorry**_ **—**.

Things like… quirks. They are… _interesting_. He likes to see what various quirks can do, sees shows on TVs showcasing people with quirks ( _heroes_ , they are, or so the TV said), sees how it's applicable in real life situations and even thinking of possible ways to counter said quirks.

It gets even more interesting when he sees how obsessed people are over heroes and villains alike, how the words are thrown so casually that Hayato has to wonder if he's somehow plunged himself into the MCU universe or some sort.

Isn't that a wonder in itself, that _superheroes_ and _supervillains_ exist, simply because of the existence of superpowers. That being a hero is an actual god friggin' _job_. It's a _profession_ , and they appear on TV. Dude, seriously. The fuck's with that?

He's seen how pickpockets are labeled as villains, sees how heroes apprehended them with vigor and all dramatics that Varia would probably find amusement from and Katsuki _wonders_.

If anyone takes Katsuki's past life into account, then he _can_ be considered as a supervillain.

(Katsuki wants to laugh.

A simple purse thief, a simple hooligan on the street, desperate people desperate to live—how they're so easy to be labeled as _villains_ , when for him "villain" is something more, something deeper.

Villains are heinous. Villains are serial killers and terrorists and human traffickers, villains are people hell bent on revenge they'll take everyone down with them for the sake of it, villains are people obsessed with power and destruction and murder.

Villains are not pickpocketers, not petty thieves and desperate people trying to live.

The usage of such word, so _easily and effortlessly_ —

He wants to laugh).

Katsuki doesn't dwell on it much, since he can still remember how much Katsuki prior Hayato's awakening wanted to be a hero. _Still does,_ actually. It's funny, how even when the old Katsuki hadn't been able to remember Hayato, they were… similar, in a way.

Katsuki wants to be a hero so he can prove himself; wants to be the best of the best, wants everyone to see that he's the strongest, the _best_. Wants to make a place for himself, an indisputable first place. Wants to show what he's made of, what he's capable of. Wants, wants, _wants_.

Hayato wanted to prove himself. Wanted to have a place to call home. Wanted to show his worth so he could be accepted, wanted to and willing to do anything so he could still have that place, that position. Wanted to show his precious people of his capabilities, of his power and strength and resolve.

Wanted to protect his precious people.

Looking down at his fists, Katsuki wonders if his priority has shifted a little bit.

He still wants to show that he's capable, wants to show that he's _there_ and he can _do_ things if he puts his mind into it. But he doesn't want to boast his strength and knowledge anymore, not to the people who don't even matter to him.

Above all, he wants to protect. Wants to find his precious people, even if maybe, _maybe_ he won't be able to see Tenth or his famiglia and allies ever again, he still… _still_ , wants to be Bakugou Katsuki who has his own precious people. Wants to find them and protect them, and maybe this time he won't die so abruptly, maybe this time, he can… He can live.

He'll start with his parents.

With his mother and father, who are around this time around, who will take care of him this time around.

Yes, yes, yes, yes. He'll start with them, his precious people.

(Does he still want to be a hero, though?

Katsuki looks at the recording of the Number One hero, All Might, and lets himself wonder.

He doesn't really know. Not yet).

* * *

 **Review please!**


	3. Chapter 3

**[ THREE: DEKU ]**

Katsuki has recently realized something that has managed to slip past his mind for quite a while.

School.

Or to be more specific, _kindergarten._

Imagine his shock when he realizes that for someone his age, he has to go to kindergarten like any other kids like him. He's been excused for a week or two because of his little quirk accident (and more that follows, because ouch, his quirk is hard to control), but now that he's shown that he's stable, he needs to go back.

Holy shit, he has to go to _kindergarten_. He has to meet small little kids! He'll meet brats like Lambo and only this time they won't be Family like Lambo, what the _fuck_. Does his mother want him to suffer? Even though Katsuki's childishness lingers—because really, he _is_ a kid, past life or not—the memories of being Hayato is enough to make him grimace in distaste at the thought of spending time with kids.

Kids are wonderful, sometimes, especially if they're nice little ones like I-Pin or Fuuta, and he guesses Lambo can be cute too, but mostly in his teenage years, Hayato had thought of Lambo like an annoying little brother. Stuck to him like a burr and made him soft sometimes, but gave him headaches nevertheless. The amount of times teenage Hayato threatened to blow Lambo up weren't little, after all.

Now, for Katsuki to willingly step into kindergarten, where there are probably smol Lambos around, screaming kids with most likely newly developed and uncontrolled quirks? Katsuki would rather crawl under his bed and scream. He'll rather train to control his quirk (his hands still accidentally blow up on him sometimes, it sucks) than meet tiny Lambos. What if he gets irritated and loses control of his quirk? He might end up blowing something up and setting those kids on fire.

Oh god, at this point Katsuki is basically a fire hazard, _what the fuck_. He can't be trusted around kids, he'll accidentally kill them or something!

"Mom, _no_ ," Katsuki grouches out. He's wrapped himself with his blanket like a burrito, glaring ferociously (or as ferociously as he's able to as a four year old) like an offended cat. He hisses loudly when his mom tugs on his comfortable burrito wrap, to which his mom simply responds by shaking him around harder.

Seriously, Katsuki's family are wild as _fuck_. His father is more mellow, but his mom? Loud. And Katsuki, if his four year old memories are to be trusted, is equally loud. It took him quite a while to compartmentalize between his mom when he was Hayato and his current mom, but he managed to do it in the end. It's easy now, to treat his mom as his real mom because honestly, _she is_.

He just had a hard time because before this, before his reawakening, when he was no-one else but Hayato, he only knew of Lavina. The gentle piano tutor, his mother who died before she could take care of him as a mother, before Hayato even _knew_ she was his mother.

But now Mitsuki is here, too. His loud, foul-mouthed mother, who takes no shit from anybody—not even her own family. There has to be some repercussions to be loud both in voice and in actions if Katsuki were a normal child; the amount of times his mom smacked his head are a _lot_. If Katsuki were not Hayato, he has an inkling he'll end up communicating with punches more than with words as a child, considering his mom's way of educating him. Granted, Katsuki is a little bit of a little shit, even when without Hayato's memories. But armed with Hayato's memories? It only gives him a little bit of nostalgia.

Violence isn't a rare sight within any mafia families, after all. Heck, as loving his family was in his childhood years, his father used to let Bianchi feed him poisoned cookies out of love. _Bianchi_ fed him poisoned food out of _love_. Whether that love his father exhibited was for his daughter who tried her best or his illegitimate son who was foaming at the mouth, he wouldn't know. He _does_ know, however, that Bianchi, with her violent and eccentric side, truly loved him. But hey, trauma and stomachache aside, at least he got stronger poison resistance from it.

Speaking of poison resistance, wouldn't that be nice if Katsuki has it too?

Katsuki blinks, some sort of an epiphany building itself in his mind. He's familiar with his sister's poison cooking. Even if he's not the Poison Scorpion, he's sure he can replicate it with the right ingredients. With that, he can slowly build up his poison resistance! He couldn't make those random worms though, not that he wants to, really. He doesn't even _know_ how his sister could have that, but she had the Poison Touch, so he's content to chalk it up as yet another weirdness Mafiosi in his old world had. Ignorance is bliss, after all.

Although his world is relatively peaceful, since he's nothing but a four year old kid ( _dammit_ ) and he's a civilian ( _DAMMIT_ ), if in the future he really ends up pursuing the hero career (he still grimaces at the thought of "hero". What a puny title given to puny humans trying to obtain fame and money. Where even is the sincerity? The Tenth would balk at these kinds of people, truly), he would need at least some poison resistance.

Building up poison resistance, especially since he's young, sounds like a pretty great idea.

"Kat. Su. Ki!" His mom's voice cuts off his deep thought, Katsuki yelping when she forcefully rips him out of his very comfortable burrito. "Why aren't you wearing your uniform yet, you difficult kid?!"

Katsuki scrambles to his soft blankets to no avail, his mom having grabbed his legs to dangle him upside down. "Agh, mom!" He yells, wiggling around in place. Damn his four year old strength and dexterities! "I told you I don't wanna!"

"And I told you that's _bullshit!_ " She shouts back, having put him on the bed and starting to tug on his All Might shirt. "You're going to school whether you want it or not!"

It's embarrassing, but Mitsuki manages to strong arm his uniform onto him (a pretty soft baby blue and yellow shorts. It's so cute and soft, very not Hayato's style that Katsuki wants to cry a little) and drag him to the kitchen so he can eat breakfast, Katsuki yelling all the while.

His old man only eats his omelet in peace, the _traitor_!

And so, Katsuki is dropped off to the kindergarten. His mom dropped him off without much fanfare, simply patting his head and telling him to behave (" _or else, you dipshit."_ Man, he wants to fight his mom, but _man_ , he loves his mom) before she leaves for work.

At the gates, children cry and yell. He can already see some children napping, slobbering and playing. He spots a few tugging each other's hair or weakly punching each other, and Katsuki skillfully turns away. He's not getting in children's petty fighting shit, no way in hell.

But this world truly is fantastic, this weird heroism system and slobbering children aside.

There are children with body shapes, colors and additions to their body—whether they're horns or wings or even extra limbs—ones that would be labeled as extra weird in his past life. There are children whose quirks have manifested: a kid making little flowers grow, a kid with particularly devastating sneeze blowing everything away, and much more.

For a while, Katsuki is distracted at the sight of such quirks.

And then, a tiny voice.

"Kacchan?"

Katsuki blinks. Blinks again.

Huh.

That voice's familiar.

Katsuki turns towards the source of said voice, and sees a boy with curly green hair.

Green hair. Wide green eyes. Chubby cheeks.

It takes Katsuki approximately 0.3 seconds to arrange his memories together and remember.

"Ah!" He says, out of reflex more than anything, chubby finger pointing at the boy. "Deku."

While the boy—Deku—smiles brightly at the greeting (fuckin' weird), Katsuki freezes in place. Because… his name is not Deku. He remembers, before, how pre-quirk Katsuki declared boldly that Deku is Deku because Katsuki can read. Of course, he's a tiny genius even without Hayato's memories, but his name _isn't_ Deku.

Thinking about it, Katsuki definitely knows Deku isn't Deku because, well. They're childhood friends, and that's basically weird not to know your own friend's name. Even Hayato knew of Turf Top's and Baseball Idiot's name, regardless of the nicknames he bestowed upon them.

Post-quirk Katsuki thinks what pre-quirk Katsuki did… it's done out of a child's small malicious intent to tease.

(False, he knows pre-quirk Katsuki wants to insult him. But now that he's Hayato and Katsuki, he wonders the merit of putting down someone who isn't actively trying to bring him down).

Technically speaking, he can stop calling Deku 'Deku' now. It's not a pleasant nickname after all. But well, he's Katsuki as much as he is Hayato. Hayato gave everyone insulting nicknames. Even his most precious people, he gave nicknames. (Turf top, Baseball Idiot, Idiot Cow—he hopes they're fine, that they're safe. Hopes they're with Tenth and protecting him even now. Hopes that they're happy and safe and _alive_ ).

That is why, after a few seconds of hesitation, Katsuki simply bellows. "Deku!"

"Yes!" Deku—Izuku—says automatically, hands stiff beside him as if he's a soldier awaiting a command. His green eyes are wide, bemused and skittish but still so, so innocent. Katsuki _wonders_.

"Why the hell are you acting like that?" He ends up saying, red eyes narrowed. His flames flared inside of him, and Katsuki _wonders_.

"N-nothing!" Deku stutters out. "I just—I didn't think you'd be here today, Kacchan!"

"Ha?" Katsuki blinks, frown apparent. "Am I not allowed to go to school?" Because _thank fuck_ if that's the case. He can call his mom and be at home, studying in his own pace, investigating more about his quirk and flames and about _heroes_.

"That's not what I meant!" Aw, shit. He had been hoping too. Deku flounders for a little bit more, his hands flailing beside him. His actions remind him so much of his Tenth that it hurts. His frown deepens at that thought, his eyes shadowed.

His Boss. Tenth. Tsuna. He hopes he's alright. Hopes he's alive, breathing and well. He hopes he's forgiven Hayato for dying. For being too weak that he didn't make it out alive.

"A-Are you okay, Kacchan?" Katsuki blinks, not realizing that Deku has stepped closer to him. Damn his four year old senses. His child senses not yet the ones he had when he was the Tenth's right hand man. Deku is hovering near him, his worry apparent. Tentatively, he grabs onto Katsuki's arm.

Katsuki's flame _flares_.

"I-if you're not feeling well, we can go to the teacher!" He suggests helpfully, green eyes gazing worriedly at Katsuki, who can only stare at him wide eyed. That was—His flame was—

"Kacchan?"

Katsuki rips his hand out of Deku's grip, red eyes staring at Deku's hand as if it's an offending piece of limb.

"…'m fine," he manages to say. "Whatever, Deku." He avoids Deku's gaze and power walks his way to what he remembers to be his class. What kind of class named its class Peach? A kindergarten, apparently. He's in a class named Peach. Fuck his life.

He studiously ignores Deku's presence near him for a few hours as the child hovers worriedly.

Ignores how his flame reaches out.

 _Damn you pre-quirk Katsuki_ , he thinks as he stabs a paper with his red crayon. _Why must you have a troublesome person with dormant flames be close to you?_

In hindsight, Katsuki knows why. People with flames, the ones who haven't bonded with others, they're more likely to feel a pull toward other flame users. And when one becomes active, dormant users will feel at ease to be near them. The more close they are, the more likely those with dormant flames to be awakened. Such is the case with Vongola's Tenth Generation.

Tenth (his seal aside) and the Guardians are mostly flame-active. They've been using their flames unconsciously throughout their daily lives. An example would be Turf Top with his muscles, allowing him to run around Japan three times by _feet_ because of his Sun Activation skill, even when he hadn't really known how to use said flames consciously. But his little sister, Kyoko, she wasn't an active flame user. When they fought Byakuran, Kyoko was declared 'null'.

But years being with Tenth and the others helped her dormant flames to be awakened, and ten years later she was a skilled Mist flame user.

Hayato was a Storm. Katsuki is no different.

His flame went active, a few days after his quirk manifested. It lays still inside of him until he gathers enough resolve to pull it back out to be used, but it's _there_.

And Deku's flame is dormant.

He doesn't know what Deku's is. What he knows is that his flame had reached out that morning. It reached out because Deku has a dormant flame just waiting to be activated. Reached out because his flame declared Deku is close enough to Katsuki to deserve his flame being activated.

Reached out because here, Katsuki's flames has no bond binding him to anybody.

No Tenth. No Baseball Idiot. No Guardians. No Vongola.

Katsuki _hates_ that.

( _Hayato hates that_ ).

But watching as Deku fumbles around with his words, in an attempt to figure out Katsuki's quirk, Katsuki can only scowl and throw a crayon at Deku's face.

Deku yelps, and Katsuki scolds him.

"Deku, stop being annoying! The teacher will just announce it later during lunch!"

"S-Sorry, Kacchan!"

It hurts.

* * *

 **Finally, after a long long wait, Hayatsuki is back! ;w; Katsuki is still Katsuki but with Hayato's mind, and it's sometimes a bit difficult for him to adapt in this world. Not to mention the sudden flashbacks and thoughts to his precious old life... Poor Hayatsuki.**

 **Poor Deku though, he really can't catch a break. Tsk, tsk.**

 **This chapter is basically:**

 **Hayatsuki: bitch i have to go to school? fuck no**

 **Mitsuki: you think i accept no as an answer? bitch**

 **Hayatsuki: kids are annoying**

 **Izuku: exists**

 **Hayatsuki: you remind me of Juudaime i would like it if you disappear from my sight**

 **Izuku: has a dormant flame**

 **Hayatsuki: oh come ON**

 **Review please! Visit my twt natanije and give some tip to the tip-jar linked there if you want! Tell me what you think about Hayatsuki! And Deku! They'll be friends soon, maybe, if Hayatsuki isn't too pissy about it. We'll see!**

 **Thank you for reading!**


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